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← Let's scan the whole planet with LiDAR

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Showing Revision 8 created 08/10/2020 by Erin Gregory.

  1. The most astounding place I've ever been
    is the Mosquitia Rain Forest in Honduras.
  2. I've done archaeological fieldwork
    all over the world,
  3. so I thought I knew what to expect
    venturing into the jungle,
  4. but I was wrong.
  5. For the first time
    in my life, I might add.
  6. (Laughter)

  7. First of all, it's freezing.

  8. It's 90 degrees, but you're
    soaking wet from the humidity,
  9. and the canopy of trees is so thick
    that sunlight never reaches the surface.
  10. You can't get dry.
  11. Immediately, I knew that
    I hadn't brought enough clothing.
  12. That first night, I kept feeling things
    moving underneath my hammock,
  13. unknown creatures brushing and poking
    against the thin nylon fabric.
  14. And I could barely sleep
    through all the noise.
  15. The jungle is loud. It's shockingly loud.
  16. It's like being downtown
    in a bustling city.
  17. As the night wore on,

  18. I became increasingly frustrated
    with my sleeplessness,
  19. knowing I had a full day ahead.
  20. When I finally got up at dawn,
  21. my sense of unseen things
    was all too real.
  22. There were hoofprints, paw prints,
  23. linear snake tracks everywhere.
  24. And what's even more shocking,
  25. we saw those same animals in the daylight,
  26. and they were completely unafraid of us.
  27. They had no experience with people.
  28. They had no reason to be afraid.
  29. As I walked toward the undocumented city,
    my reason for being there,

  30. I realized that this was the only place
    that I had ever been
  31. where I didn't see
    a single shred of plastic.
  32. That's how remote it was.
  33. Perhaps it's surprising to learn
  34. that there are still places on our planet
    that are so untouched by people,
  35. but it's true.
  36. There are still hundreds of places
    where people haven't stepped for centuries
  37. or maybe forever.
  38. It's an awesome time
    to be an archaeologist.

  39. We have the tools and the technology
  40. to understand our planet
    like never before.
  41. And yet, we're running out of time.
  42. The climate crisis threatens to destroy
    our ecological and cultural patrimony.
  43. I feel an urgency to my work
  44. that I didn't feel 20 years ago.
  45. How can we document everything
    before it's too late?
  46. I was trained as
    a traditional archaeologist

  47. using methodologies that
    have been around since the '50s.
  48. That all changed in July of 2009
  49. in Michoacán, Mexico.
  50. I was studying the ancient
    Purépecha Empire,
  51. which is a lesser known
    but equally important contemporary
  52. of the Aztec.
  53. Two weeks earlier, my team
    had documented an unknown settlement,
  54. so we were painstakingly mapping,
    building foundations by hand --
  55. hundreds of them.
  56. Basic archaeological protocol
    is to find the edge of a settlement

  57. so you know what you're dealing with,
  58. and my graduate students
    convinced me to do just that.
  59. So I grabbed a couple of CLIF Bars,
    some water, a walkie,
  60. and I set out alone on foot,
  61. expecting to encounter "the edge"
    in just a few minutes.
  62. A few minutes passed.
  63. And then an hour.
  64. Finally, I reached
    the other side of the malpais.
  65. Oh, there were ancient
    building foundations all the way across.
  66. It's a city?
  67. Oh, shit.
  68. (Laughter)

  69. It's a city.

  70. Turns out that this
    seemingly small settlement

  71. was actually an ancient urban megalopolis,
  72. 26 square kilometers in size,
  73. with as many building foundations
    as modern-day Manhattan,
  74. an archaeological settlement so large
  75. that it would take me
    decades to survey fully,
  76. the entire rest of my career,
  77. which was exactly how I didn't want
    to spend the entire rest of my career --
  78. (Laughter)

  79. sweating, exhausted,

  80. placating stressed-out
    graduate students --
  81. (Laughter)

  82. tossing scraps of PB and J sandwiches

  83. to feral dogs,
  84. which is pointless, by the way,
  85. because Mexican dogs
    really don't like peanut butter.
  86. (Laughter)

  87. Just the thought of it bored me to tears.

  88. So I returned home to Colorado,

  89. and I poked my head
    through a colleague's door.
  90. "Dude, there's gotta be a better way."
  91. He asked if I had heard
    of this new technology called LiDAR --
  92. Light Detection And Ranging.
  93. I looked it up.
  94. LiDAR involves shooting
    a dense grid of laser pulses
  95. from an airplane to the ground's surface.
  96. What you end up with
    is a high-resolution scan
  97. of the earth's surface
    and everything on it.
  98. It's not an image,
  99. but instead it's a dense,
    three-dimensional plot of points.
  100. We had enough money in the scan,
  101. so we did just that.
  102. The company went to Mexico,
  103. they flew the LiDAR
  104. and they sent back the data.
  105. Over the next several months, I learned
    to practice digital deforestation,

  106. filtering away trees, brush
    and other vegetation
  107. to reveal the ancient
    cultural landscape below.
  108. When I looked at my first visualization,

  109. I began to cry,
  110. which I know comes
    as quite a shock to you,
  111. given how manly I must seem.
  112. (Laughter)

  113. In just 45 minutes of flying,

  114. the LiDAR had collected
    the same amount of data
  115. as what would have taken decades by hand:
  116. every house foundation,
  117. building, road and pyramid,
  118. incredible detail,
  119. representing the lives
    of thousands of people
  120. who lived and loved and died
    in these spaces.
  121. And what's more, the quality of the data
  122. wasn't comparable to traditional
    archaeological research.
  123. It was much, much better.
  124. I knew that this technology would change
    the entire field of archaeology
  125. in the coming years,
  126. and it did.
  127. Our work came to the attention
    of a group of filmmakers

  128. who were searching for a legendary
    lost city in Honduras.
  129. They failed in their quest,
  130. but they instead documented
    an unknown culture,
  131. now buried under a pristine
    wilderness rain forest,
  132. using LiDAR.
  133. I agreed to help interpret their data,
  134. which is how I found myself deep
    in that Mosquitia jungle,
  135. plastic-free and filled
    with curious animals.
  136. Our goal was to verify
    that the archaeological features

  137. we identified in our LiDAR
  138. were actually there on the ground,
  139. and they were.
  140. Eleven months later, I returned
    with a crack team of archaeologists
  141. sponsored by the
    National Geographic Society
  142. and the Honduran government.
  143. In a month, we excavated over 400 objects
  144. from what we now call
    the City of the Jaguar.
  145. We felt a moral and ethical responsibility
    to protect this site as it was,

  146. but in the short time that we were there,
  147. things inevitably changed.
  148. The tiny gravel bar where we first
    landed our helicopter was gone.
  149. The brush had been cleared away
    and the trees removed
  150. to create a large landing zone
    for several helicopters at once.
  151. Without it,
  152. after just one rainy season,
  153. the ancient canals that we
    had seen in our LiDAR scan
  154. were damaged or destroyed.
  155. And the Eden I described
    soon had a large clearing,
  156. central camp,
  157. lights
  158. and an outdoor chapel.
  159. In other words, despite our best efforts
    to protect the site as it was,
  160. things changed.
  161. Our initial LiDAR scan
    of this City of the Jaguar
  162. is the only record of this place
    as it existed just a few years ago.
  163. And broadly speaking,

  164. this is a problem for archaeologists.
  165. We can't study an area
    without changing it somehow,
  166. and regardless, the earth is changing.
  167. Archaeological sites are destroyed.
  168. History is lost.
  169. Just this year, we watched in horror

  170. as the Notre Dame Cathedral
    went up in flames.
  171. The iconic spire collapsed,
  172. and the roof was all but destroyed.
  173. Miraculously, the art historian
    Andrew Tallon and colleagues
  174. scanned the cathedral in 2010 using LiDAR.
  175. At the time, their goal was to understand
    how the building was constructed.
  176. Now, their LiDAR scan is the most
    comprehensive record of the cathedral,
  177. and it'll prove invaluable
    in the reconstruction.
  178. They couldn't have anticipated the fire
  179. or how their scan would be used,
  180. but we're lucky to have it.
  181. We take for granted that our cultural
    and ecological patrimony

  182. will be around forever.
  183. It won't.
  184. Organizations like SCI-Arc
    and Virtual Wonders
  185. are doing incredible work
  186. to record the world's historic monuments,
  187. but nothing similar exists
    for the earth's landscapes.
  188. We've lost 50 percent of our rain forests.
  189. We lose 18 million acres
    of forest every year.
  190. And rising sea levels will make cities,
    countries and continents
  191. completely unrecognizable.
  192. Unless we have a record of these places,
  193. no one in the future
    will know they existed.
  194. If the earth is the Titanic,
  195. we've struck the iceberg,
  196. everyone's on deck
  197. and the orchestra is playing.
  198. The climate crisis threatens to destroy
    our cultural and ecological patrimony
  199. within decades.
  200. But sitting on our hands and doing nothing
  201. is not an option.
  202. Shouldn't we save everything
    we can on the lifeboats?
  203. (Applause)

  204. Looking at my scans
    from Honduras and Mexico,

  205. it's clear that we need
    to scan, scan, scan
  206. now as much as possible,
  207. while we still can.
  208. That's what inspired the Earth Archive,
  209. an unprecedented scientific effort
  210. to LiDAR-scan the entire planet,
  211. starting with areas
    that are most threatened.
  212. Its purpose is threefold.

  213. Number one: create a baseline record
    of the earth as it exists today
  214. to more effectively mitigate
    the climate crisis.
  215. To measure change, you need
    two sets of data:
  216. a before and an after.
  217. Right now, we don't have
    a high-resolution before data set
  218. for much of the planet,
  219. so we can't measure change,
  220. and we can't evaluate
    which of our current efforts
  221. to combat the climate crisis
  222. are making a positive impact.
  223. Number two: create a virtual planet

  224. so that any number of scientists
    can study our earth today.
  225. Archaeologists like me
    can look for undocumented settlements.
  226. Ecologists can study tree size,
  227. forest composition and age.
  228. Geologists can study hydrology,
  229. faults, disturbance.
  230. The possibilities are endless.
  231. Number three: preserve
    a record of the planet

  232. for our grandchildren's grandchildren,
  233. so they can reconstruct and study
    lost cultural patrimony in the future.
  234. As science and technology advance,
  235. they'll apply new tools, algorithms,
  236. even AI to LiDAR scans done today,
  237. and ask questions that we
    can't currently conceive of.
  238. Like Notre Dame,

  239. we can't imagine how these
    records will be used.
  240. But we know that they'll
    be critically important.
  241. The Earth Archive is the ultimate gift
    to future generations,
  242. because the truth be told,
  243. I won't live long enough
    to see its full impact,
  244. and neither will you.
  245. That's exactly why it's worth doing.
  246. The Earth Archive is a bet
    on the future of humanity.
  247. It's a bet that together,
  248. collectively,
  249. as people and as scientists,
  250. that we'll face the climate crisis
  251. and that we'll choose
    to do the right thing,
  252. not just for us today
  253. but to honor those who came before us
  254. and to pay it forward
    to future generations
  255. who will carry on our legacy.
  256. Thank you.

  257. (Applause)